1. Field of the Invention
The present invention relates to an apparatus and a method for detecting flaws in a silicon wafer, such as scratches on surface thereof, chips on edges thereof, or flaws inside the wafer.
2. Description of the Prior Art
In the fabrication of electronic devices, semi-conducting silicon material in the form of wafers is most frequently used for forming electronic circuits in a miniature scale. In the processing of electronic wafers, the wafer surface need multi processes for gaining a well planarization so as to satisfy the requirement of integrated circuit processing. The last procedure is wafer polishing, sometime the wafer will broken during the process. That will spend much time to clean the broken material on the machine platform, not only waste the process material, but also delay the manufacturing speed.
The reasons of wafer broken are usually due to some defects caused by preceding processes. In prior art, the wafer is usually immediately washed following the preceding process. After washing, checking if the wafer has any chip, scratch, or pollution by visual inspection, then proceeding with the wafer polishing. However, the traditional visual inspection cannot detect the flaws inside the wafer.
In the traditional technology of detecting, after the electronic wafer finished, using an optical microscope with chemical solution for inspecting the scratch, or using X-ray machine for inspecting structure flaws. However that equivalent is very expansive and spending much time. If using that for inspecting the wafer flaws before wafer polishing, that not fit the manufacturing efficiency and cost.
If there is an apparatus or method could sift the abnormal wafer out immediately and quickly before wafer polishing so as to reduce the wafer broken during manufacturing, the invention is desired.